EC_GFP_SIMPLE_METHOD(3)    Library Functions Manual    EC_GFP_SIMPLE_METHOD(3)

NAME
     EC_GFp_simple_method, EC_GFp_mont_method, EC_METHOD_get_field_type -
     obtain EC_METHOD objects

SYNOPSIS
     #include <openssl/ec.h>

     const EC_METHOD *
     EC_GFp_simple_method(void);

     const EC_METHOD *
     EC_GFp_mont_method(void);

     int
     EC_METHOD_get_field_type(const EC_METHOD *meth);

DESCRIPTION
     The elliptic curve library provides a number of different implementations
     through a single common interface.  Each implementation is optimised for
     different scenarios.  An implementation is represented by an EC_METHOD
     structure.

     When constructing a curve using EC_GROUP_new(3), an implementation method
     must be provided.  The functions described here all return a const
     pointer to an EC_METHOD structure that can be passed to EC_GROUP_new(3).
     It is important that the correct implementation type for the form of
     curve selected is used.

     For Fp curves the lowest common denominator implementation is the
     EC_GFp_simple_method() implementation.  All other implementations are
     based on this one.  EC_GFp_mont_method() adds the use of Montgomery
     multiplication (see BN_mod_mul_montgomery(3)).

     EC_METHOD_get_field_type() identifies what type of field the EC_METHOD
     structure supports.  If the field type is Fp, then the value
     NID_X9_62_prime_field is returned.  If the field type is F2^m, then the
     value NID_X9_62_characteristic_two_field is returned.  These values are
     defined in the <openssl/objects.h> header file.

RETURN VALUES
     All EC_GFp*() functions always return a const pointer to an EC_METHOD
     structure.

     EC_METHOD_get_field_type() returns an integer that identifies the type of
     field the EC_METHOD structure supports.

SEE ALSO
     BN_mod_mul_montgomery(3), d2i_ECPKParameters(3), EC_GROUP_copy(3),
     EC_GROUP_new(3), EC_KEY_new(3), EC_POINT_add(3), EC_POINT_new(3)

HISTORY
     EC_GFp_simple_method() and EC_GFp_mont_method() first appeared in OpenSSL
     0.9.7 and have been available since OpenBSD 3.2.

     EC_METHOD_get_field_type() first appeared in OpenSSL 0.9.8 and has been
     available since OpenBSD 4.5.

Linux 6.8.7-arch1-1             April 27, 2023             Linux 6.8.7-arch1-1